<!DOCTYPE html>
<html>
<body>
<p><a id="myAnchor" href="../../www.example.com/test.htm#part2">Example link</a></p>
<p>Click the button to change the protocol part of the link above.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("myAnchor").protocol = "mailto:";
document.getElementById("demo").innerHTML = "The protocol was changed from 'http://' to 'mailto://'.";
}
</script>
</body>
</html>